In this world, there are two kinds of women – the ones who make a lot of noise during sex and ones who don’t. Some women give you a play by play of everything they

like or want you to do while building up to their orgasm in a very vocal way. Others enjoy the experience but they don’t feel the need to share the experience with the world so loudly. It’s two very different styles and there aren’t many people who fall in between – so why do some women shake the walls while others simply shake the bed? Science decided to find out.

Gayle Brewer, from the University of Central Lancashire, and Colin Hendrie, from the University of Leeds, conducted a research study in 2011 about how vocal some people are during sex – a trait they called “copulatory vocalization”. Their less than sexy clinical name aside, the duo set out to find out why some women scream, others moan and still more just kick back and enjoy the sounds of silence.

The team approached 71 heterosexual women between the ages of 18 and 48 to learn specifically about how loud they were during sex. In the end, they learned that many of the women did make noise although not necessarily while they were having an orgasm. More than half reported they used moans and other forms of vocal encouragement to actually speed up their partner’s orgasm, since their own theatrics tended to help him get off more quickly. In addition to helping speed things along, more than 85% of the women reported they also did it to boost their lover’s self-esteem.

In their report published in the Archives of Sexual Behavior, the group observed, “While female orgasms were most commonly experienced during foreplay, copulatory vocalizations were reported to be made most often before and simultaneously with male ejaculation.” This conclusion suggests women get their vocalizations in time with their partner’s orgasm more often than their own.

But that isn’t to say that women are using their vocal approvals and encouragement to dupe their partners. After all, there are examples of how women achieve orgasm throughout pop culture. Movies like “When Harry Met Sally” and shows like Sex and the City have made the female orgasm something that is openly discussed and widely imitated. So to some degree, women may simply be repeating what they’ve learned over the past few years.

But women shouldn’t fake an orgasm when they’re really not feeling it. If you want to exaggerate a bit that’s one thing, but pretending a man is giving you the time of your life when really he’s barely competing with the prime time lineup won’t do either of you any favors. A vocal orgasm sends a clear message that a man is doing something right, so it is important that women use that encouragement wisely.

This study didn’t focus on how vocal men were with their partners and it also didn’t offer much insight on how men react to these differences in volume levels. To be sure, many men enjoy the encouragement – and the show – these women provide but it usually comes down to finding someone who is a good fit for you when it comes to sexual style.

In the end, some women are louder probably because that’s what they think they are meant to do and, of course, because it adds to the fun of sex. As with most other sexual behaviors, further research is already underway which could give us even more insight into what makes women tick and how to make them tick even harder.